U.S. patent number 6,896,493 [Application Number 10/372,255] was granted by the patent office on 2005-05-24 for scroll compressor.
This patent grant is currently assigned to LG Electronics Inc.. Invention is credited to Young Il Chang, Yang Hee Cho, Yoo Chol Ji, Myung Kyun Kim.
United States Patent |
6,896,493 |
Chang , et al. |
May 24, 2005 |
Scroll compressor
Abstract
Disclosed is a scroll compressor enabling a significant height
reduction to use a space of a system efficiently when the scroll
compressor is applied to such systems as a refrigerator, an air
conditioner, and the like. A compressor housing forms an exterior,
a crankcase is fixed inside the compressor housing, a boss is
formed at a central portion thereof to protrude downward, and a
bearing hole is formed in a center thereof. A stator having a
hollow shape is fixed to a lower side of the crankcase, and a rotor
is provided to maintain a clearance between an outer
circumferential surface of the stator and an inner circumferential
surface thereof. A crankshaft is provided to pass through the
bearing hole and is fixed to the rotor to revolve together with the
rotor, wherein an eccentric pin is formed on an upper side thereof.
A orbiting scroll is connected to the eccentric pin, and a fixed
scroll fixed to an upper side of the crankcase to form a
compression chamber together with the orbiting scroll.
Inventors: |
Chang; Young Il (Seoul,
KR), Cho; Yang Hee (Seoul, KR), Kim; Myung
Kyun (Inchon-kwangyok-shi, KR), Ji; Yoo Chol
(Inchon-kwangyok-shi, KR) |
Assignee: |
LG Electronics Inc. (Seoul,
KR)
|
Family
ID: |
31982513 |
Appl.
No.: |
10/372,255 |
Filed: |
February 25, 2003 |
Foreign Application Priority Data
|
|
|
|
|
Aug 27, 2002 [KR] |
|
|
P10-2002-0050907 |
Aug 27, 2002 [KR] |
|
|
P10-2002-0050908 |
Aug 27, 2002 [KR] |
|
|
P10-2002-0050909 |
Aug 27, 2002 [KR] |
|
|
P10-2002-0050906 |
|
Current U.S.
Class: |
417/410.5;
310/266; 310/51; 418/94 |
Current CPC
Class: |
F04C
18/0215 (20130101); F04C 23/008 (20130101) |
Current International
Class: |
F04C
18/02 (20060101); F04C 23/00 (20060101); F04B
017/03 () |
Field of
Search: |
;417/410.5,415,410.3,424.1,424.2 ;310/51,266 ;418/94 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Koczo, Jr.; Michael
Attorney, Agent or Firm: Greenblum & Bernstein,
P.L.C.
Claims
What is claimed is:
1. A scroll compressor comprising: a compressor housing forming an
exterior of the compressor; a crankcase fixed inside the compressor
housing, a boss is formed at a central portion of the crankcase to
protrude downward and a bearing hole is formed in a center of the
crankcase; a stator having a hollow shape is fixed to a lower side
of the crankcase; a rotor provided to maintain a clearance between
an outer circumferential surface of the stator and an inner
circumferential surface of the rotor; a crankshaft positioned to
pass through the bearing hole and fixed to the rotor to revolve
together with the rotor and an eccentric pin is formed on an upper
side of the crankshaft; a orbiting scroll connected to the
eccentric pin; and a fixed scroll fixed to an upper side of the
crankcase to form a compression chamber together with the orbiting
scroll.
2. The scroll compressor of claim 1, wherein the boss of the
crankcase is positioned in the hollow portion of the stator.
3. The scroll compressor of claim 1, wherein the stator is
screw-coupled with a bottom of the crankcase to be fixed
thereto.
4. The scroll compressor of claim 2, wherein an inner
circumferential surface of the stator is force-fit into an outer
circumferential surface of the boss of the crankcase to be fixed to
the crankcase.
5. The scroll compressor of claim 1, wherein at least one balance
hole is formed in the rotor.
6. The scroll compressor of claim 5, wherein the at least one
balance hole comprises at least one upper balance hole formed on an
upper side of a circumference of the rotor in a same direction of
an eccentric direction of the eccentric pin of the crankshaft.
7. The scroll compressor of claim 5, wherein the at least one
balance hole comprises at least one lower balance hole formed on a
lower side of a circumference of the rotor in a direction opposite
to an eccentric direction of the eccentric pin of the
crankshaft.
8. The scroll compressor of claim 5, wherein the rotor comprises: a
cylindrical rotor housing having an opening at an upper side; and a
rotor conductor fitted in an inner circumferential surface of the
rotor housing.
9. The scroll compressor of claim 8, wherein at least one
interconnecting hole configured to have an oil or gas pass
therethrough is formed in a bottom of the rotor housing.
10. The scroll compressor of claim 8, wherein at least one balance
hole is further formed in the rotor housing.
11. The scroll compressor of claim 10, wherein the at least one
balance hole comprises at least one upper balance hole formed on an
upper side of a circumference of the rotor in a same direction of
an eccentric direction of the eccentric pin of the crankshaft.
12. The scroll compressor of claim 10, wherein the at least one
balance hole comprises at least one lower balance hole formed on a
lower side of a circumference of the rotor in a direction opposite
to an eccentric direction of the eccentric pin of the
crankshaft.
13. The scroll compressor of claim 1, further comprising a
sub-frame provided at a lower side of the crankshaft to support a
lower end of the crankshaft.
14. The scroll compressor of claim 1, further comprising: a thrust
face formed on an upper side of the bearing hole of the crankcase
to have a step difference with another portion of the upper side;
and a thrust portion protruding from a circumference of the
crankshaft, wherein a lower face of the thrust portion is supported
by the thrust face.
15. The scroll compressor of claim 14, wherein the thrust portion
protrudes along the circumference of the crankshaft on a boundary
of a lower face of the eccentric pin of the crankshaft.
16. The scroll compressor of claim 1, further comprising: an oil
supplying path passing through the crankshaft in an upper/lower
direction; an oil return path passing through the crankcase from a
center towards an outside; and an oil guide member guiding oil from
the oil return path to a lower side of the rotor.
17. The scroll compressor of claim 16, wherein the oil guide member
is a channel type guide plate having an opening formed along a
length direction of one side toward an inner wall of the compressor
housing.
18. The scroll compressor of claim 17, wherein an upper side of the
guide plate extends gradually toward an edge of the guide
plate.
19. The scroll compressor of claim 16, wherein the oil guide member
is a guide pipe having one end connected to the oil return path and
the other end disposed in a space of the lower side of the
rotor.
20. The scroll compressor of claim 19, wherein the guide pipe is
provided at least in part out side of the compressor housing.
Description
RELATED APPLICATION
This application claims the benefit of the Korean Application Nos.
P2002-50906, P2002-50907, P2002-50908 and P2002-50909 filed on Aug.
27, 2002, which is hereby incorporated by reference in their
entireties.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scroll compressor, and more
particularly, to an outer rotor type scroll compressor.
2. Description of the Related Art
Generally, a scroll compressor is a device for compressing a fluid
kept in a compression chamber by varying a volume of the
compression chamber constructed with movable and fixed scrolls by
rotating the orbiting scroll. The scroll compressor has an
efficiency greater than that of a reciprocating or rotary
compressor, small vibration, and low noise, and can be made light
in weight. Hence, the scroll compressor is used in various fields
nowadays.
Constitution and operation of a scroll compressor according to a
related art are explained by referring to the attached drawings as
follows.
Referring to FIG. 1A, a scroll compressor according to a related
art includes a compressor housing 1, a crankcase 2, an inner rotor
type motor 3, a crankshaft 4, an orbiting scroll 5, and a fixed
scroll 6.
The compressor housing 1 forms an exterior of the compressor, and
various components are provided in the compressor housing 1.
The crankcase 2 is fixed inside the compressor housing 1. A boss 2a
protrudes downward from a central portion of the crankcase 2, and a
bearing hole 2b penetrates a center of the boss 2a.
The inner rotor type motor 3 is provided at a lower side of the
crankcase 2, and includes a rotor 3a and a stator 3b. The rotor 3a,
as shown in FIG. 1A, is fixed to a circumference of the crankshaft
4 to revolve together with the crankshaft 4. The stator 3b is fixed
inside the compressor housing 1. And, the rotor 3a is positioned in
a hollow central portion of the stator 3b so that an inner
circumferential surface of the stator 3b is spaced by a
predetermined interval from an outer circumferential surface of the
rotor 3a.
The crankshaft 4 is coupled with the rotor 3a to revolve together.
One side of the crankshaft 4 is configured to penetrate the bearing
hole 2b formed in the crankcase 2. And, an eccentric pin 4a is
formed at an upper end of the crankshaft 4 near the crankcase 2.
Further, a bearing is provided between the bearing hole 2b and the
crankshaft 4 to guarantee smooth rotation of the crankshaft 4.
The orbiting scroll 5 is coupled with the eccentric pin of the
crankshaft 4 to rotate.
The fixed scroll 6 is coupled with the crankcase 2 to be fixed
thereto, and provides a compression chamber 6 with the orbiting
scroll 5 to compress a fluid confined in the compression chamber
6a.
Meanwhile, the scroll compressor according to the related art
further includes a plurality of counterweights canceling out an
eccentric force generated when the orbiting scroll 5, eccentric
from a rotation center, and the eccentric pin 4a of the crankshaft
4 are rotating. The counterweights, as shown in FIG. 1A, include an
upper counterweight 7 provided in a direction opposite to an
eccentric direction of the eccentric pin 4a of the crankshaft 4 and
a lower counterweight 8 provided in the same direction of the
eccentric direction of the eccentric pin 4a of the crankshaft 4
near a bottom of the rotor 3a.
Referring to FIG. 1B, the scroll compressor according to the
related art can further include a sub-frame 9 as well as the
above-explained elements. The sub-frame 9 is provided at a lower
side of the crankshaft 4. One side of the sub-frame 9 is fixed to
an inner lower side of the compressor housing 1 to support a bottom
of the crankshaft 4, thereby preventing the crankshaft 4 from
falling due to gravity.
Referring to FIG. 1C and FIG. 1D, the scroll compressor according
to the related art has an oil supply path for smooth lubrication of
rotational and frictional portions and a return structure for
returning the supplied oil. And, they are explained briefly in the
following.
First of all, oil 1b is stored in an inner lower side of the
compressor housing 1.
A lower end of the crankshaft 4 is positioned to dip in the stored
oil 1b, and an oil supplying path 4b is formed inside the
crankshaft 4 to be inclined in a direction extending farther from
the rotation center of the crankshaft 4 toward an upper side.
Moreover, an oil return path 2c is formed in the crankcase 2 to
penetrate from a central portion to one side of the crankcase 2,
and is formed for returning the oil 1b, which has been supplied to
the center of the crankcase 2 through the oil supplying path 4b, to
a lower side of the compressor housing 1.
Further, an oil path 1a, as shown in FIG. 1C and FIG. 1D, is formed
between an inner face of the compressor housing 1 and an outer
circumferential surface of the stator 3b to guide the oil 1b
drained through the oil return path 2c to the lower side of the
compressor housing 1.
The above-constituted scroll compressor according to the related
art operates as follows.
First of all, power is applied to turn the rotor 3a and crankshaft
4, and then the turning crankshaft 4 revolves the orbiting scroll 5
coupled with the eccentric pin 4a. As the orbiting scroll 5
revolves, a fluid locked inside the compression chamber formed
between the fixed and orbiting scrolls 6 and 5 becomes
compressed.
Simultaneously, while the crankshaft 4 turns, the oil 1b in the
lower side of the compressor housing 1 is elevated along the oil
supplying path 4b by a centrifugal force to lubricate the bearing
unit at a side of the crankcase 2. Most of the supplied oil 1b is
returned to the lower side of the compressor housing 1 along the
oil return path 2c and the oil path 1a to be kept in store.
However, the above-constituted scroll compressor according to the
related art has the following problems or disadvantages.
First of all, the rotor 3a provided at the lower side of the
crankcase 2 is fixed to the circumference of the crankshaft 4 and
the crankshaft 4 is provided to penetrate the bearing hole 2b
formed in the center of the boss 2a of the crankcase 2. Hence, the
boss 2a of the crankcase 2 and the rotor 3a occupy the spaces at
upper and lower sides of the crankshaft 4, thereby setting
structural limitation on reducing the height of the machine.
Secondly, the upper counterweight 7 is provided in the direction
opposite to the eccentric direction of the eccentric pin 4a of the
crankshaft 4 over the rotor 3a to be disposed between the boss 2a
of the crankcase 2 and the top surface of the rotor 3a. Hence, the
height of the machine increases additionally.
Thirdly, the inner rotor type motor 3 has the rotor 3a located
inside the stator 3b. And, an outer diameter of the inner rotor
type motor 3 is smaller than that of an outer rotor type motor
having a rotor placed outside a stator. In order to cancel out the
eccentric force when one angular speed .omega. of the counterweight
is equal to the other under the same condition, a mass m should be
increased to be inversely proportional to a distance r between a
rotation center and a weight center of the counterweight using the
equation of `F=mr.omega..sup.2 ` for finding a centrifugal force of
the counter weight. Hence, the size, i.e. height, of the
counterweight should be increased to increase the mass with the
same material, whereby the height of the machine is increased more
to enhance the structural limitation together with the
above-explained second problem of the related art.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a scroll
compressor that substantially obviates one or more problems due to
limitations and disadvantages of the related art.
An object of the present invention is to provide a scroll
compressor enabling a substantial reduction in height to use a
space of a system efficiently when the scroll compressor is applied
to such systems as a refrigerator, an air conditioner, and the
like.
Another object of the present invention is to provide a scroll
compressor enabling a reduction in product cost and simplifying an
assembly process by replacing a heavy and large counterweight of
the related art.
A further object of the present invention is to provide a scroll
compressor enabling to a reduced product cost and a simplified
assembly process by replacing a sub-frame of the related art to
reduce a height of the compressor.
Another further object of the present invention is to provide a
scroll compressor preventing returning oil from dispersing by a
rotor.
Additional advantages, objects, and features of the invention will
be set forth in part in the description which follows and in part
will become apparent to those having ordinary skill in the art upon
examination of the following or may be learned from practice of the
invention. The objectives and other advantages of the invention may
be realized and attained by the structure particularly pointed out
in the written description and claims hereof as well as the
appended drawings.
To achieve these objects and other advantages and in accordance
with the purpose of the invention, as embodied and broadly
described herein, a scroll compressor according to the present
invention includes a compressor housing forming an exterior
housing, a crankcase fixed inside the compressor housing wherein a
boss is formed at a central portion thereof to protrude downward
and a bearing hole is formed in a center thereof, a stator having a
hollow shape to be fixed to a lower side of the crankcase, a rotor
provided to maintain a clearance between an outer circumferential
surface of the stator and an inner circumferential surface thereof,
a crankshaft provided to pass through the bearing hole and fixed to
the rotor in part to revolve together with the rotor wherein an
eccentric pin is formed on an upper side thereof, an orbiting
scroll connected to the eccentric pin, and a fixed scroll fixed to
an upper side of the crankcase to form a compression chamber
together with the orbiting scroll.
Preferably, the boss of the crankcase is embedded in the hollow
portion of the stator.
Preferably, the stator is screw-coupled with a bottom of the
crankcase to be fixed thereto.
More preferably, an inner circumferential surface of the stator is
fitted into an outer circumferential surface of the boss of the
crankcase by force to be fixed.
Preferably, at least one balance hole is formed in the rotor.
More preferably, the balance hole comprises at least one upper
balance hole formed on an upper side of a circumference of the
rotor in a same direction of an eccentric direction of the
eccentric pin of the crankshaft.
More preferably, the balance hole comprises at least one lower
balance hole formed on a lower side of a circumference of the rotor
in a direction opposite to an eccentric direction of the eccentric
pin of the crankshaft.
More preferably, the rotor includes a cylindrical rotor housing
having an opening at an upper side and a rotor conductor fitted in
an inner circumferential surface of the rotor housing.
More preferably, at least one interconnecting hole having an oil or
gas passage there through is formed in a bottom of the rotor
housing.
More preferably, at least one balance hole is further formed in the
rotor housing.
More preferably, the balance hole comprises at least one upper
balance hole formed on an upper side of a circumference of the
rotor in a same direction of an eccentric direction of the
eccentric pin of the crankshaft.
More preferably, the balance hole comprises at least one lower
balance hole formed on a lower side of a circumference of the rotor
in a direction opposite to an eccentric direction of the eccentric
pin of the crankshaft.
Preferably, the scroll compressor further includes a sub-frame
provided at a lower side of the crankshaft to support a lower end
of the crankshaft.
Preferably, the scroll compressor further includes a thrust face
formed on an upper side of the bearing hole of the crankcase to
have a step difference and a thrust portion protruding from a
circumference of the crankshaft wherein a lower face of the thrust
portion is supported by the thrust face.
More preferably, the thrust portion protrudes along the
circumference of the crankshaft on a boundary of a lower face of
the eccentric pin of the crankshaft.
Preferably, the scroll compressor further includes an oil supplying
path passing through the crankshaft in an upper/lower direction, an
oil return path passing through the crankcase from one side of
center to an outside, and an oil guide member guiding oil from the
oil return path to a lower side of the rotor.
More preferably, the oil guide member is a channel type guide plate
having an opening formed along a length direction of one side
toward an inner wall of the compressor housing.
More preferably, an upper side of the guide plate gradually extends
toward an edge of the guide plate.
More preferably, the oil guide member is a guide pipe having one
end connected to the oil return path and the other end disposed in
a space of the lower side of the rotor.
More preferably, the guide pipe is provided outside the compressor
housing in part.
It is to be understood that both the foregoing general description
and the following detailed description of the present invention are
exemplary and explanatory and are intended to provide further
explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further
understanding of the invention and are incorporated in and
constitute a part of this application, illustrate embodiment(s) of
the invention and together with the description serve to explain
the principle of the invention. In the drawings:
FIG. 1A and FIG. 1B illustrate cross-sectional views of an inner
rotor type scroll compressor according to a related art;
FIG. 1C illustrates a cross-sectional view for showing a flow of a
lubrication oil in FIG. 1B;
FIG. 1D illustrates a cross-sectional view along a cutting line
I--I in FIG. 1C;
FIG. 2A illustrates a cross-sectional view of a scroll compressor
according to one embodiment of the present invention;
FIG. 2B illustrates a bird's-eye view of a stator according to the
present invention;
FIG. 2C illustrates a cross-sectional view that shows another
example of a crankcase and a stator coupled with each other
according to the present invention;
FIG. 2D illustrates a cross-sectional view of a lower counter
weight according to another embodiment of the present
invention;
FIG. 3A illustrates a cross-sectional view of an eccentric force
canceling means according to another embodiment of the present
invention;
FIG. 3B and FIG. 3C illustrate bird's-eye views of rotor housings
in FIG. 3A, respectively;
FIG. 4A illustrates a cross-sectional view of a crankshaft
supporting means according to another embodiment of the present
invention;
FIG. 4B illustrates a cross-sectional view of a modifying example
of FIG. 4A;
FIG. 5A illustrates a cross-sectional view of a lubrication oil
circulation structure according to one embodiment of the present
invention;
FIG. 5B illustrates a bird's-eye view of a guide plate in FIG. 5A;
and
FIG. 5C and FIG. 5D illustrate cross-sectional views of oil guiding
members according to another embodiments of the present invention,
respectively.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to the preferred embodiments
of the present invention, examples of which are illustrated in the
accompanying drawings. Wherever possible, the same reference
numbers will be used throughout the drawings to refer to the same
or like parts.
FIG. 2A illustrates a cross-sectional view of a scroll compressor
according to one embodiment of the present invention.
Referring to FIG. 2A, a compressor housing forms an exterior
housing and various elements are provided inside the compressor
housing 10.
A crankcase 20 is fixed inside the compressor housing 10, and a
boss 21 protrudes downward from a central portion of the crankcase
20. And, a bearing hole 22 penetrates through a central portion of
the boss 21 upward and downward.
Unlike the related art, the present invention uses an outer rotor
type motor, as shown in FIG. 2A, to turn a crankshaft 50. The outer
rotor type motor used by the present invention includes a stator 30
and a rotor 40, and specific constitution and operation of the
outer rotor type motor are explained as follows.
First of all, the stator 30, as shown in FIG. 2B, is constructed
with a plurality of electrical steel plates 31 having empty central
parts to form a hollow shape. In this case, each of the electrical
steel plates 31 includes a hollow portion 30a at its central part,
a plurality of radial slots 31a at its outer circumferential
surface, and a plurality of screw coupling holes 31b at its inner
circumferential surface to fix the stator 30 to a bottom of the
crankcase 20. And, the slots 31a and screw coupling holes 31b of
the electrical steel plates 31 are stacked on each other to be
aligned reciprocally. And, a coil 32 is wound on the slots 31a to
complete the stator 30. The above-constituted stator 30 is fixed to
the bottom of the crankcase 20.
And, the rotor 40, as shown in FIG. 2A, includes a rotor housing 41
and rotor conductor 42. The rotor housing 41, as shown in FIG. 3B
and FIG. 3C, has a cylindrical shape constructed with a
circumferential portion and a bottom portion, and an upper side of
the rotor housing 41 is open. And, the rotor conductor 42 includes
a plurality of hollow electrical steel plates (not shown in the
drawing) stacked on each other, and is pushed inside an inner
circumferential surface of the rotor housing 41. The
above-constituted rotor 40, as shown in FIG. 2A, has its inner
circumferential surface separated from an outer circumferential
surface of the stator 30, and is provided inside the stator 30 to
maintain a clearance therebetween.
Meanwhile, the crankshaft 50, as shown in FIG. 2A, is provided to
pass through the bearing hole 22 and the hollow portion 30a of the
stator 30, and an eccentric pin 51 with a predetermined
eccentricity is formed at an upper portion of the crankshaft 50
over the bearing hole 22. And, one side of the crankshaft 50 is
fixed to one side of the rotor 40, for example a bottom of the
rotor housing 41. The above-constituted crankshaft 50 revolves
together with the rotor 40, and a bearing is provided between the
crankshaft 50 and bearing hole 21 for smooth revolution.
A orbiting scroll 5, as shown in FIG. 2A, is coupled with the
eccentric pin 51 of the crankshaft 50 to carry out a turning
movement when the crankshaft 50 revolves.
And, a fixed scroll 6 is fixed to an upper portion of the crankcase
20, and forms a compression chamber 6a together with the orbiting
scroll 5 to compress a fluid confined in the compression chamber 6a
when the orbiting scroll 5 carries out the turning movement.
In order to reduce a height of the above-constituted scroll
compressor according to the present invention, the boss 21 of the
crankcase 20, as shown in FIG. 2A, is positioned in the hollow
portion 30a of the stator 30.
In this case, the stator 30, as shown in FIG. 2A, can be fixed to
the bottom of the crankcase 20 by screw coupling.
Moreover, the present invention enables fixing the stator 30 and
the boss 21 of the crankcase 20 to each other in another way. For
instance, an inner circumferential surface of the stator 30, as
shown in FIG. 2C, can be inserted inside an outer circumferential
surface of the boss 21 of the crankcase 20 to be fixed thereto
directly. And, such insertion is carried out by thermal driving or
cold driving. Further, in order to reinforce the fixing force and
support the crankshaft 50 safely after the boss 21 and stator 30
have been fitted to each other, a length of the boss 21 can be
increased.
Meanwhile, the scroll compressor according to the present invention
can further include an eccentric force canceling means for
canceling out or balancing an eccentric force generated from the
turning movement of the orbiting scroll 5.
For instance, a counterweight is a good example of the eccentric
force canceling means. And, at least one counterweight is provided
at one side of the rotor 40, for example the rotor housing 41.
Such counterweights include upper and lower counterweights 61 and
62.
The upper counterweight 61 is provided on an upper side of the
rotor 40 disposed in a direction opposite to an eccentric direction
of the eccentric pin 51 of the crankshaft 50, as shown in FIG. 2A
and FIG. 2C, for example an upper side of the rotor housing 41
disposed in the direction opposite to the eccentric direction of
the eccentric pin 51 of the crankshaft 50.
And, the lower counterweight 62 is provided on a lower side of the
rotor 40 disposed in the same direction of the eccentric direction
of the eccentric pin 51 of the crankshaft 50, as shown in FIG. 2A
and FIG. 2C, for example a lower side of the rotor housing 41
disposed in the same direction of the eccentric direction of the
eccentric pin 51 of the crankshaft 50.
In this case, the lower counterweight 62 is provided at a lower
face of the rotor 40, as shown in FIG. 2A and FIG. 2C, for example
a lower face of the bottom of the rotor housing 41, or a lower part
of a circumference of the rotor 40, for example a lower part, as
shown in FIG. 2D, of a circumference of the rotor housing 41.
The above-constituted upper and lower counterweights 61 and 61 are
attached to one side of the rotor 40, for example the rotor housing
41 or are configured as extensions of one body.
Moreover, the present invention can include another eccentric force
canceling means.
For instance, a balance hole is a good example of another eccentric
force canceling means. At least one balance hole is provided at one
side of the rotor 40, for example the rotor housing 41 to cancel
out the eccentric force generated from the revolution of the
crankshaft 50.
Such balance holes include upper and lower balance holes 41b and
41c.
The upper balance hole 41b is formed on an upper side of the rotor
40 disposed in the same direction of the eccentric direction of the
eccentric pin 51 of the crankshaft 50, as shown in FIGS. 3A to 3C,
for example an upper side of the rotor housing 41 disposed in the
same direction of the eccentric direction of the eccentric pin 51
of the crankshaft 50.
And, the lower balance hole 41c is formed on a lower side of the
rotor 40 disposed in a direction opposite to the eccentric
direction of the eccentric pin 51 of the crankshaft 50, as shown in
FIG. 3B and FIG. 3C, for example a lower side of the rotor housing
41 disposed in the direction opposite to the eccentric direction of
the eccentric pin 51 of the crankshaft 50.
In this case, the lower balance hole 41c is provided at a lower
face of the rotor 40, as shown in FIG. 3A and FIG. 3B, for example
a lower face of the bottom of the rotor housing 41, or a lower part
of a circumferential surface of the rotor 40, for example a lower
part, as shown in FIG. 3C, of a circumference of the rotor housing
41.
Each of the counterweights increases a mass of one side of the
rotor 40 to cancel out the eccentric force generated from the
revolution of the crankshaft 50, while each of the balance holes
decreases the mass of one side of the rotor 40 to cancel out the
eccentric force generated from the revolution of the crankshaft 50.
Hence, the balance holes and counter weights are disposed
oppositely when they are formed.
Meanwhile, the scroll compressor according to the present invention
can further includes a crankshaft support for supporting the
crankshaft to prevent the crankshaft 50 from drooping downward or
falling due to gravity.
There is a sub-frame 70, as shown in FIG. 2A, as an example of the
crankshaft support. The sub-frame 70 is provided at a lower side of
the crankshaft 50. One side of the sub-frame 70 is fixed to an
inner side of the compressor housing 10 to have the other side of
the sub-frame 70 support a lower end of the crankshaft 50. Besides,
it is obvious to apply a device for guaranteeing smooth revolution
to a contact area between the lower end of the crankshaft 50 and
the sub-frame 70 such as a bearing and the like. Hence, explanation
for such a device is skipped in this description.
Moreover, the crankshaft support means of the present invention can
be implemented differently. Other examples are shown in FIG. 4A and
FIG. 4B, and are explained in the following.
Referring to FIG. 4A and FIG. 4B, the crankshaft support includes a
thrust face or surface 23 formed on the crankcase 20 and a thrust
portion 52 formed on the crankshaft 50. The thrust face 23 has a
step difference from an upper side of the bearing hole 22 of the
crankcase 20, and the thrust portion 52 protrudes from a
circumference of the crankshaft 50 so that a bottom of the thrust
portion 52 is contacted with the thrust face 23 to be supported.
And, the thrust portion 52 protrudes along the circumference of the
crankshaft 50 on a boundary of the lower face of the eccentric pin
51 of the crankshaft 50.
The thrust face 23 and thrust portion 52 play a role in maintaining
a sliding contact on revolution of the crankshaft 50. Hence, the
friction at the contact area should be minimized. For this, the
present invention constructs the thrust face and portion 23 and 52
with an oil-less bearing, as shown in FIG. 4A, or an additional
thrust bearing 80, as shown in FIG. 4B, provided between the thrust
face and portion 23 and 52.
Meanwhile, the scroll compressor according to the present invention
further includes a structure of oil supply and return to lubricate
the revolving and frictionally contacting, which is explained by
referring to FIGS. 5A to 5D as follows.
First of all, oil 11 is stored in an inner lower side of the
compressor housing 10.
A lower end of the crankshaft 50 is provided to be dipped in the
stored oil or oil reservoir 11, and an oil supplying path 50a is
formed inside the crankshaft 50 to pass through a lower most end of
the crankshaft 50 and a upper most end of the crankshaft 50, i.e.
an upper end of the eccentric pin 51 in upper/lower direction. In
this case, the oil supplying path 50a is formed to pass through the
crankshaft 50 so that a lower end is located at a revolution center
of the crankshaft 50 and an upper end is located at a position
remote from the revolution center of the crankshaft 50. If the oil
supplying path 50 is formed inclined, the oil 11 flowing in the
lower end of the oil supplying path 50a is elevated to the upper
end by a centrifugal force to be drained.
Moreover, an oil return path 20a is formed in the crankcase 20 to
extend from a central portion to one side of the frame 20, and is
formed for guiding the remaining oil 11, which has been supplied to
the upper side of the crankcase 20 through the oil supplying path
50a for the lubrication of the bearing unit, to an inner wall of
the compressor housing 10.
In order to prevent the oil, which has been guided by the oil
return path 20a and drained to the inner wall of the compressor
housing 10, from being dispersed by the revolving rotor 40 and
guide the oil to a lower side of the rotor 40, i.e. an inner lower
side of the compressor housing 10, as shown in FIG. 5C and FIG. 5D,
the present invention further includes an oil guide member 90, 190,
and 290. The present invention needs the oil guide member for the
following reasons.
First of all, different from the scroll compressor according to the
related art using the inner rotor type motor having the rotor
placed at the inner circumferential surface of the stator, the
scroll compressor according to the present invention uses the outer
rotor type motor having the rotor 40 placed at the outer
circumferential surface of the stator 30, whereby the rotor housing
41 occupies all the space between the central part and inner
circumferential surface of the compressor housing 10 to revolve. If
the present invention has the oil return structure of the related
art, the oil dropping on the lower side of the compressor housing
10 is dispersed by the rotor 40 after being drained from the oil
return path 20a. Besides, the dispersed oil flows inside the
compression chamber 6a together with a gas such as refrigerant and
the like. Hence, the oil as an incompressible fluid unnecessary for
compression is compressed to increase a pressure of the scroll
compressor, reduce a volume efficiency by the oil flowing in the
compressor room, and increase an impelling loss of the rotor 40. In
the worst case, the oil fails to be returned properly to cause lack
of oil. Therefore, the present invention using the outer rotor type
motor requires the additional oil guide members for preventing the
problems from occurring.
The oil guide member can be implanted in various ways, and some
examples are explained by referring to the attached drawings as
follows.
Referring to FIG. 5A and FIG. 5B, the oil guide member includes a
guide plate 90. The guide plate 90 has a channel shape having an
opening along a length direction of one side, and is provided
between the compressor housing 10 and rotor 40 so that the opening
is arranged to face the inner wall of the compressor housing 10.
And, in order to guide the entire oil drained through the oil
return path 20a, an upper portion of the guide plate 90, as shown
in FIG. 5B, has a funnel shape extending in area toward the edge of
the upper portion.
Referring to FIG. 5C and FIG. 5D, the oil guide member includes a
guide pipe. One end of the guide pipe is connected to the oil
return path 20a and the other end is disposed in a lower side space
of the rotor 40, i.e. an inner lower side space of the compressor
housing 10. The above-provided guide pipe, as shown in FIG. 5C, can
have an external guide pipe 190 exposed in part outside the
compressor housing 10, or an internal guide pipe 290, as shown in
FIG. 5D, embedded entirely inside the compressor housing 10.
Moreover, the present invention includes at least one
interconnecting hole 41a, through which an oil or gas can pass, as
shown in FIG. 2A or FIG. 3B, formed in the bottom of the rotor
housing 41. And, a plurality of the interconnecting holes 41a are
preferably formed along a circumferential direction of the bottom
of the rotor housing 41.
The interconnecting holes 41a of the present invention are formed
in the bottom of the rotor housing because of the following
reason.
First of all, once the scroll compressor starts to operate, the oil
11 stored in the lower side of the compressor housing 10 is
elevated to the upper side of the crankcase 20 along the oil
supplying path 50a formed inside the crankshaft 50, lubricates the
bearing unit at the side of the crankcase 20, and falls downward,
in this order. In this case, if there is no interconnecting hole
41a, the oil having lubricated the bearing unit gathers on the
bottom of the rotor housing 41. Hence, the present invention forms
the interconnecting hole 41a in the bottom of the rotor housing 41
to move the oil smoothly to the lower side of the compressor
housing 10 as well as make the gas flow in and out smoothly.
Operation of the above-constituted scroll compressor according to
the present invention is similar to that of the related art, and is
explained as follows.
First of all, a power is applied to turn the rotor 40 and
crankshaft 50, and then the turning crankshaft 50 revolves the
orbiting scroll 5 coupled with the eccentric pin 51. When turning,
the crankshaft 50 is supported stably by the crankshaft support
with the cancellation of the eccentric force by the eccentric force
cancellation device. As the orbiting scroll 5 carries out the
turning movement, the fluid confined inside the compression chamber
between the fixed and orbiting scrolls 6 and 5 becomes
compressed.
Simultaneously, while the crankshaft 50 turns, the oil 11 in the
lower side of the compressor housing 10 is elevated along the oil
supplying path 50a by the centrifugal force to lubricate the
bearing unit at a side of the crankcase 20. Most of the elevated
oil 11 is returned to the lower side of the compressor housing 10
along the oil return path 20a and oil guide member to be stored.
Moreover, some of the oil 11 falls on the lower side after
lubricating the bearing unit, and then is returned to the lower
side of the compressor housing 10 through the interconnecting hole
41a of the rotor housing 41 to be stored.
Therefore, the above-constituted and -operating scroll compressor
according to the present invention provides a reduction in its
overall height to be remarkably smaller than that of the related
art due to the following reasons.
First of all, the boss 21 of the crankcase 20 is provided to be
disposed in the hollow portion 30a of the stator 30 of the rotor
40. Hence, the overall height of the scroll compressor can be
reduced as much as the length of the boss 21 embedded in the hollow
portion 30a.
Secondly, since the rotor 40 is provided at a position different
from that of the boss 21 of the crankcase 20, it is able to avoid
the interference between the upper counterweight 61 and boss 21
even if the upper counterweight is provided on the top of the rotor
40. The present invention need not secure an additional space as
high as the height of the counterweight, thereby enabling a
reduction in the overall height of the scroll compressor.
Thirdly, when the eccentric force cancellation means is the balance
holes, the upper counterweight is unnecessary to be provided on the
top of the rotor 40, thereby enabling a reduction in the overall
height of the scroll compressor as much as the space for holding
the counterweight.
Finally, since an outer diameter of the rotor 40 of the outer rotor
type motor of the present invention is greater than that of the
inner rotor type motor of the related art, it is able to reduce a
mass m in inverse proportion to a distance r between a rotation
center and a weight center of the counterweight using the equation
of `F=mr.omega..sup.2 ` for finding a centrifugal force of the
counter weight to cancel out the eccentric force. In other words,
assuming that the same centrifugal force is attained, the rotor 40
of the present invention has the diameter relatively greater than
that of the related art to reduce the mass of the counterweight
relatively. In this case, the reduction of the mass means that the
size or height of the counterweight of the same material can be
decreased. Hence, the overall height of the scroll compressor can
be reduced. Meanwhile, if the eccentric force cancellation means is
the balance hole, the same principle is applicable to reduce the
overall height of the scroll compressor.
Accordingly, the scroll compressor according to the present
invention has the following effects or advantages.
First of all, the present invention decreases the height of the
scroll compressor, thereby enabling a reduction in product cost as
well as making efficient use of the space of the system such as a
refrigerator, an air conditioner, or the like.
Secondly, since the outer diameter of the rotor of the present
invention is greater than that of the related art, the torque can
be increased in proportion to the location of the gap between the
inner circumferential surface of the rotor and the outer
circumferential surface of the stator.
Thirdly, the present invention enables a reduction in the size and
weight of the counterweights if the eccentric force cancellation
means of the present invention is constructed with the
counterweights. And, the present invention enables a reduction in
the weight of the compressor remarkably if the eccentric force
cancellation means of the present invention is constructed with the
balance holes.
Fourthly, the counterweights which was an additional in the related
art are removed from the compressor to reduce the product cost as
well as simplify the number of the assembly process if the
eccentric force cancellation means of the present invention is
constructed with the balance holes.
Fifthly, the sub-frame which was an additional in the related art
can be removed from the compressor to reduce the product cost as
well as simplify the number of the assembly process if the
crankshaft support is constructed with the thrust face and
portions.
Finally, the present invention includes the oil guide member to
return the oil to the inner lower side of the compressor housing
without the dispersion of the oil after lubrication, thereby
enabling preventing the pressure and volume efficiency of the
scroll compressor from decreasing.
It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention.
Thus, it is intended that the present invention covers the
modifications and variations of this invention provided they come
within the scope of the appended claims and their equivalents.
* * * * *